Understand

Get in

the main reason to get in Muang Ngeun is Passing the border From Ban Huay Kon (Thailand)
Meny don't know but the border with Thailand ( Ban Huay Kon – Muang Ngeun ) is open for a while (year or two ) also for foreigns .

you can get a visa on arivel an the both sides of the border. ( you need to bring a picture for the visa )

the main problem is that the bus to UdomXai is at 12 from The Bus station.

So if you don't want to spend a night In Muang Ngeun ( It is not so bad thing ) you Should pass the border in the morning.